Does anyone know if Esri publishes its workflow on how the Business Analyst or GeoEnrichment data is disaggregated to different geographies?
We use a number of techniques to build data starting with the smallest unit area - the block in the US. We aggregate and apportion up and across different geographies from there. You can find documentation on the process here: https://developers.arcgis.com/rest/geoenrichment/api-reference/data-apportionment.htm
For the whole world we have a set of summary tables https://support.esri.com/en/download/7776
and for each country we have detailed descriptions of how we apportion by scale/distance e.g Canada:
https://doc.arcgis.com/en/esri-demographics/latest/regional-data/canada.htm
I hope this helps
Best wishes
Helen